I want need to do some serious carpenter bee extermination. I have 20-30 of them drilling my back deck and it’s starting to look like swiss cheese. Can I just spray them all down with the Cypermethrin or do I have to dust all the holes too?
Definitely dust the holes too. Successful carpenter bee extermination will only happen if you dust them with the Drione as explained in our CARPENTER BEE CONTROL article. Since the eggs, larvae and pupae reside in their holes, you must have something there to kill off the developing bees. Drione will be key if you want to be rid of them once and for all.